Automotive HVAC Pressure Diagnostics...

LINKS:
http://www.autodiagnosticsandpublishi...
http://www.autodiagnosticsandpublishi...

Pressure analysis diagnostics is the cornerstone of properly doing a climate control system assessment. As we all know, the HVAC systems is composed of a high and a low pressure side. The orifice tube or expansion valve is the one components in between these two refrigerant conduits. The compressor of course is the one in charge of pressurizing the refrigerant. Pressure analysis is by far the best, and probably in many cases, the only way to properly diagnose the dozens of specific issues with the automotive HVAC system.

But first, here are the various scenarios relating to pressure analysis. Before we go into it, it is important to understand what the baseline pressures should be. The normal HVAC baseline is about 39 PSI on the Low-Side, and about 250 PSI on the High-Side. How far away we deviate from this baseline, is what's going to determine our issue. Here are the different analysis scenarios.

Case 1... High pressure on the Low Side and baseline pressure on the high side. This may translate to say about ...

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